Electric sign



K. LIMPERT ELECTRIC SIGN Feb. 17. i925.

Filed Deg. l) 1921 000000000000000 0 000000000000 00000000 0p00 K; 00 000, H 0 000 a a 0 7/ L ooQ; 7 fiwoo 0000 0000 0 00 0000 0090 0000000000 000 Kg IN TOR A TTORNE Y Patented Feb. 17, 1925.

KATHERINE LIMPERT, OF NEW YORK, N. Y.

ELECTRIC SIGN.

Application filed December 1, 1921. Serial No. 519,044.

' To all whom it may concern:

Be it known that I, KATHERINE LIMPERT, a citizen of the United States, residing at New Y0rlr, in the county of New York and State of New York, have invented certain new and useful Improvements in Electric Signs, of which the following is a specification.

My invention relates to electric signs and other such illuminated displays. I aim to make the sign most effective in illumination; flexible in design and adaptability to meet varying requirements and conditions of use; easy and inexpensive to manufacture, install and adjust; and in service convenient and economical as regards both operation and maintenance. Still other advantages obtainable through the invention will appear from my description hereinafter of the best embodiments of the invention known to me.

In its broader aspects, my invention is applicable to various different types of signs,-as, for example, the two general types represented by United States Patents S. Limpert July 13, 1920 and August 3, 1920, respectively. The apparatus hereinafter described is of the type represented by Patent No. 1,346,499. An apparatus (corresponding, in some respects to Patent No. 1,348,816) wherein the broad underlying principles of my present invention are applied quite diiferently is disclosed in my companion application Serial No. 519,045, filed Dec. 1, 1921, concurrently therewith. In both cases, my inventionv affords important advantages (such as indicated above) over the corresponding prior Limpert devices. 4 In the drawings, Fig. 1 is a front view or elevation of an illuminated sign apparatus conveniently embodying my invention.

Fig. 2 is a similar view with the front of the sign (as seen in Fig. 1) broken away, and removed along the section line 22 in Fig. 3.

Fig. 3 shows a vertical cross section, taken as indicated by the line 3--3 in Fig. 2.

Fig.- 4 is a perspective or tilted view of one of the reflective illuminating devices or units shown in Figs. 1 to 3, with one part partially broken away.

Fig. 5 shows a mid section through such a unit.

Figs. 6 and 7 are diagrammatic side views Nos. 1,346,499 and 1,348,816, granted to A.

of a light source with several reflective de vices or units, illustrating the operation and advantages of my invention.

Fig. 8 is a front view illustrating the application of my invention to a sign of the so-called roof type. i

The sign shown in the drawings (Figs. 1 to 3) comprises a thin, shallow box 10, with panel or panels 11, 11 carrying the desired design,-in the present instance, the letter B,-in colors visible by day. The incandcscent'electric lamp or lamps 12, 12 here shown as source of light for the sign at night or mounted within the box 10, in sockets 13 carried by brackets 14 attached to the top and bottom ends of the box. At night, therefore, the sign design is luminously set out or outlined by the light from the lamps 12, 12 directed by reflective devices or units 15 through openings in the walls or panels 11, 11 and (in the present instance) through supplemental directing or diffusing means 17 (in the form of rounded lens-globes) provided for each unit. The interior of the box 10 may advantageously so be painted white or otherwise rendered reflective, in order that a maximum proportion of the total light from the lamps 12, 12 may ultimately find its way out through the devices 15 and be utilized.

Referring to Figs. 4, 5, 6 and 7, it will be seen that the individual reflective device ultimate luminary 15 comprises a series or group of reflector elements or strips 20 arranged to reflect the obliquely incident light coming directly from the corresponding lamp 12 approximately perpendicular or normal to the group. In the present instance, these reflector elements are strips of slat-like form, and are arranged shutterwise in a common general plane behind but approximately that of the panel or half-sign as a whole, at one side of the light source 12. The elements 20 make with the series as a whole (as represented by their common general plane) such common angle that the light of the source 12 directly incident upon them from behind is reflected and thrown forward by and between them. Ordinarily, variation in the distance of the reflective luminary unit 15 from the lamp 12 (either in the same or in different signs) will not be so great as to require an adjustable shutter-like mounting of the elements 20, or even the provision of a line of units with 110 unit 15 it a (like satin-finished silver) will oftensuffice the elements 20 set at Various diflerent fixed angles. gOfi tlfie contra-m, assuage unit, with group or set of rfictof elements 20 fixed at one universal angle, will be found satisfactory under, considerable variations in distance of units from the light source. With reflector elements 20 cf rel'a' tively narrow Width in proportion to their spacing, as shutt ng there will no m teria in f nee em t by n e .e t' .e ii lfi ts iit mf, e vice', the unit 1 5 k r ap' ""air generally and even quite uniformly luniino u's'; W hile 5th" eleIitentfjZO ef ch ultimate "ight be stan'i eu ut pf isheet metal in one piece, orunited in one single piece of glee (in-wh i seepemu ey 1ie "even be replaced with retracting prisms), I have here showni them a's Wholly separate thin fl'at, narrow 'slatsg t'vith their ends moi-ne e t ee flfi i dis ,Q h llfow frame oi lia'seal with which the leiisl? s socifated: consolidated lens and ina tr 17- 1. ay b ou d n rsu ldly' t n ment o t tan i ie fit s ee l jl e' '7 if e em i'tty pr u i et iiei fiit :5 i i f f e y designed a uise-settelight we; a large ar a tha e l s may a a e- "from almo staiiy angle of vision. lens 17 constructed m re for less like the 'bulls' eye (with slightly less space between the retracting zones), as shown, is ver Suap H ever, uite variety oflensestyill we cor y esh w (Figh frame abuts against vthe inside of the ana ll vith a rubber or other suitable a t 22 in er se emy me ee between them, and the lens 17 projects througharound holc' iiifthep'ahel. The'unit is held in placeby engagement of projecting lugs 123 (511 lens with the outside of the panel. I assembling, the unit may be instate in its pane ling rem inside-the box with :thelugs 23 in i'cgifstry with correspondifn'g'notchesfl and then turhedto'displace the lugs from the liio'tclies through which they hai e passed The elastic coili- 'tsei'n pith-t gasket 22 {tends to prevent accidental turning and iinlfocl'ring of the unit; andtfi tyliole unit 1'5 being evenly b e i i' n n tjrt t ell eh tiirn itag'ainst the friction "of the gaske za estaments 210 may be either speeuiar 0 mi P" e rfl b h y. may be f iii'etal, glass bi othermateri'al' suitably formed or treated to render i't pi' ope'rly reflective. Theyrnay be can (1 with "silver leaf, "silver "deposit, ordinary mirroring, aluminum leaf or foil or other reflecting material; and in tl l e case of glass, suchn aterial may bea'p'- p iee fither treat 01 en. A dam -metal;

show

or bystipple-etching glass With hydrofluoric acid; and applying mirroring or metallic leaf. Aluminum paint on metal or glass has also given good results.

It will be seen that in front the reflector elementeac areecveied and protected from access of dust,,dirt or other deterioratingagencies by the lenses oi' globes 17-; As sun-1n protect-ion atlt'lie rear is attot-lied by light-permeable, transparent glass cover 25 consisting er flatyp'ane *cemented,- settled for etnertis'e secured in place ina rabbet at't he rear of the fiameorbase '21. Also, use protease sever 25 tongue elements QOsecurely in place. Not onlfj does this-cover 25 keep the elements 20 and the rearofthe lens '17 free new dirt, but it is itself much more easily kept clean than they bOth-becau'se it presents but a single flat, smooth urface, and b'ecause its Vertical position minimizes adhesion and accumulation of dust on it.

7 since the shallow illuminating or reflector units '15 donot project far intothe sign box 10, the iilteiiorof thebo-X is clear andv'open.

This not till affords maximum unshaded access ofaiVai able li'glit'to ei ery unit and facilitates and eiipeditesreplacement of lamps 12 and cleaning of reflector cov crs25, buta l'so allbwsthe lamps 12 to beplaced in any position desirec, 'espeeiauythe Vertical or tip donnward position so important to the full life of the high efiicien'cy gas-filled tungsten filament lamp. The openness of the box "likewiseallows thelamp's 12 and their filaments to be placed sideWi'se toward the units 15, so that a reaterproportion of the light shall reach the units directly than ifth'e lamps had to bemounted bntlie-pa-nels 1'1, 1'1 and placed end-oh toward "the u its 15. I

The small project ion of the multi reflectolr type of illuminating unit froiinthe panel '11 gives rise to other important advantages. hi the first place, itallows one unit 15 to be. placed close behind another with reference totheir etmmoa light source (Fig. 6) Without shading or blanketing bf the "one by the other; whereas a unit26 comprising one large mirror 7-) instead-oifa number of small mirrors Would throw any unit behind it "into deep shadow. Myfsh'ab lOW non-shading multi-reflector type of illumin atingunit', therefore, gets the 'sigfnjdesigner untrammelled freedom in the Variant arrangement of unitsffor "display formation, and "enables him to illuminate his sign with a minimum number of relatively large and efiicient lamps, and yet haveall its units 15 appeai simiieriyaaa generauy luminous.

In the second place, the multi-reflector t pe "of illuminating-unit "I5 covets or 11 uminates the lens 17 completely and evenly, whereas a single mirror 26 of very considerable size may reflect relatively little light to the right-hand half of the lens 17 ,as will readily be evident from Fig. 7,so that in g any cases half the lens would appear very In the third place, the multi reflector type of illuminating unit gives the lens a much wider angle of illumination than is possible with a single reflector 26 (Fig.

7), because with it the virtual light source representedby the reflector is much closer to the lens. Without discussing the optical theory of the matter, it may be pointed out that the angle of illumination varies inversely according to the distance from the center of the lens 17 to the plane of incidence on the reflector of the ray from the center of brilliance of the source 12 that is reflected through the center of the lens. In other words, the advantage of the multirefiector type in Fig. 7 is indicated by the shortness of the distance it as compared with the distance H. A wide angle of illumination of the lens 17 means, of course, that the sign appears brilliant over a considerable angle to either side, as well as directly in front.

Still other advantages are afforded by the multi-reflector type of illuminating unit. For example, if it should prove necessary to place a lamp 12- directly behind one of the units 15 (as in Fig. 8), then the reflector elements 20 will partially shade one another to such an extent that the corresponding lens 17 will not mar the general effect of the sign by undue brilliance. This is of especial importance when it is attempted to light a whole letter with a single lamp. If this were done with the B of Figs. 1 to 3, the lamp used would need to be placed directly behind the central lens 17 (Fig. 1).

It is further to be noted that in the sign of Figs. 1 to 3 the box 10 is rendered weather-proof and practically dust-tight by the gaskets 22, and the lamps 12 are com pletely enclosed. No particular skill is required in the location of the units 15, or in their adjustment,which latter is effected by simply turning each unit one way or the other till the position of greatest brilliancy (which is that in which the reflector elements lie perpendicularly across the shortest line from the center of the light source thereto) is foimd. It is unnecessary, of course, that the twoopposite sides or panels 11, 11 be just alike. Multi-colored effects are easily obtained by using differently colored lamps for illuminating differ ent groups of units 15, or by using appro priately colored covers 25. Double or composite color effects can be obtained by simultaneously using several diflerently colored lamps to illuminate one whole group of units 15; or vari-colored effects can be obtained by flashing such lamps in alternation.

As compared with a sign in which each illuminating unit is an incandescent electric lamp, the type of sign shown in Figs. 1 to 3 affords a very considerable economy in both current consumption and lamp renewal costs. According to my invention, for example, both sides of 9. Drugs sign can be well illuminated with ten 25-watt tungsten lamps. The cost of operating such a sign on current at 6c per KIV hour is 1 per hour; whereas with all-lamp letters averaging ten 10-watt lamps apiece for each side, the operating cost would be 63 per hour. For operating the two signs five hours every evening for one year, the costs would be $27.32 and $109.50, respectively. In each of these signs, lamp replacements must be made something like twice a year, at the same cost per lamp, so that for my type of sign each renewal would cost only one-tenth as much as for the other. Since, furthermore my type employs the larger and longer-lived lamps,--less fragile, especially under vibration, because their filaments are not so fine,my type will not require such frequent renewals as the other type. In Fig. 8 is shown a sign (letter H) of the so-called roof type constructed according to my invention. In this sign, more illuminating units 15 and lamps 12 are used than in that of Figs. 1 to 3; but the principles are the same. It will be apparent to those skilled in the art that various other displays,-such as borders of steady or flashing type, friezes, or lighting fixtures,can readily be illuminated according to my invention.

The term longitudinal axis as employed in the claims has reference to the axis can tending from the front to the rear of a unit.

WVhat I claim is:

l. A reflectively illuminated display comprising a light source, and a plurality of shallow units illumined thereby cooperating to form a sign design; the individual unit comprising a multiplicity of reflector elements in a plane approximately that of the sign as a whole, a common light permeable protective cover at the side of said elements toward said light source, and a diffusing lens at the other side of said elements.

2. A reflectively illuminated display comprising a light source, and a plurality of shallow units illuminated thereby cooperating to form a display design, the individual unit comprising a series of reflector elements adapted to reflect light from said source forward between them, and diffusing means in front of said elements evenly illuminated by them.

3. An illuminated display comprising a m ees efl to uni re m d he. y

ra ng o: fer'len splay e 'gn, th

riar i l reflector elements in a ap- I' r'Q i-m e' hat 0.1 he di play s yhele- 4, An i'l'Iu'rjninate difipil y 'JQIHPIi II a ligh ae i'ce, enc, e plurality 0f gener l-y and Simi rly luminehs refle or un ts umin d ther y wep iziti g t9. orm di play de gn, th ndi ual comp ie n a eries oi i r e em nt dapted to refl c n rmal y ligh n i n ehliqu ly t e h seriee, I i

5. A r fi m display 1 1 i? empr' s ne' a rie f a il j e eflecto e men s a ged sh t r-wise or. refle t n of igh fren e ind orward betw n them. nd difi sing le s i om; 01 d, e em A r fle tive enier unl t 'wmp si a S r s of fit elmntis adapted t ree t l ht 'em beh nd. f rward betwe t'lger'n, and di fi'using means-in frqnt offs aiiid lem s e enly llilmi' at'ed by h m- A e ect e d p ay un l iqmpris ni a series 01 slat-like reflectfer elements "51- re ged shu ter-Wi e refl ti of gh fr m b h nd o w d, b tw en hem will a eernmen protective cover at one side of said ele'lnen't s." V v 8 A r flect d splay unit c mpr s n e i s o "r ee or lements n afi ommen mane m king "e qmm n angle, the wi h, 11110111111021 ght pe m ab prote tiv c e 0 ai leme ts; 7 v

An ll m t d splay Comp is ng a ight soer ez nd a phii eli'ty 19f ge e ally lu-m nq flect-or u ts -lluimi ed "thereby cQ'Qpemt Hg t fe m disp ay si n, the indivi'drml nnit 'c0rn]g)ri sing"4 eriee bf 'relatirely arrow refiect r l men s r 17efletme; ferward q ely in ident li h fr t es ur e,

10. An illuminated display comprising a ht. 61 nd 1 p l'e'l y ge era'lly l minous r ct units i um ned th reby cooperating to form a. display design, the

ndividual un cq p i inge se es of h l k eflecf ement mi-ranged shutt rwi or eflec iwln 7 lig t 01? aid: so rce incit m b llied fm' e d betw en $1 1.

1 A ge ally umino s e'l mafi lum nary un t o a ian di p ay formati comp ising a. single ries Q ativ y m row, reflector "Strips for reflecting forward between them light in'cicl'enf qbli qulely to unit for refle'e'tifol r oflight; frqln behind *forward between them, s0 narrow in proporti e't heir p c ng as o vi t ma e ehadi ng'z l s arngngst' themselves and make th uni n e f 'ge el y lum n mean wh by s d l gh di s d- In testimony whereof I have hereunto sig my KATHERINE: LI EL 

